Method of making brushes



April 7, 1953 H. W. BIBLE, JR

METHOD OF MAKING BRUSHES 2 SHEETS SHEET 1 Filed July 14, 1949 April 7, 1953 H. w. BIBLE, JR 2,634,167

METHOD OF MAKING BRUSHES Filed July 14, 1949 2 SHEETS-SHEET 2 rill! UNITED STATES PATENT OFFICE METHOD OF MAKING BRUSHES Howard W. Bible, In, Buffalo, N. Y., assignor to Hewitt-Robins Incorporated, Bufialo, N. Y.

Application July 14, 1949, SerialNo. 104,665

rmsmvfieon relates to a novel method of making anew brushmhaving metal or similar bristles.

- "Therpresent invention relates particularly to a brush wherein the :bond or connection between .the bristles "and thecarrier or support for the bristles is unique and, further, to a method wherein this bond or connection is broughtabout ..in a .novel 'buthighly practical and efiicient manner. .More specifically, the present invention relates to brushes wherein the inner ends of the bristles areiembedded in rubber or other material having similar physical properties.

' In brushes made-according to the present invention the "components of the brush are asisembled inia. novel manner and as a result the physical parts of the ultimate brush bear a novel relationship to each other, the parts being physi- "cally interlocked ina manner which gives the ultimate in physical strength and resistance to disintegration. The possibility of bristles becoming loose or disassociated from the brush proper under extreme centrifugal forces or other potentially damaging effects is, for all practical 'apurposes, eliminated.

a broad generality the idea of employing rubber or similar material for setting brush bristles in :a holder is not new. While reference is had herein to metal bristles and binding wires,

by way of example, the principles of the present invention, insofar as they are applicable, may

be employed in .brushes having non-metallic bristles, such for example as nylon and fibre glass, and the binding means may likewise be non-metallic.

Certain of the advantages of brush bristles set in rubber have previously been recognized but fell short of full attainment because of other practical objections and disadvantages.

Other objects and advantages are novel to brushes constructed according to the present invention.

In one practical embodiment of the present invention a circular rotary brush having wire bristles is adapted to perform a wide variety of operations in the industrial arts such as cleaning and polishing and other abrasive functions. In

'ePrior brushes intended generally tov have @bristles andbinding wires or similar anchorin 4 Claims. (01. 300-21) means set in rubber or the like have invariably contained voids in greater or lesser degree, particularly at the root portions of the bristles where they are bunched together most inti- Jmately, with a resultant reduction in strength,

efficiency, length of life and safety. In the brushor the present invention the root portions of the is frequent.

The accompanying drawings and the ensuing detailed'desoription set forth, by way of example,'one form of the brush of the present invention and the detailed steps of a method for manufacturing the same. However, it is to be understood that the specific brush and method are set forth for illustrative reasons and that the principles of the present invention are notlimited thereto, or otherwise than as in the appended claims.

The drawings herein illustrate a brush having radial bristles, but it is to be understood that the principles of the present invention apply equally in the construction of a brush wherein the bristles lie in an axial direction to form a so-called cup-shaped brush. Also, the bristles may be arranged in a helical row or they may extend in a straight line, for attachment to the periphery of a supporting cylinder or otherwise. In other words, the present invention is concerned with the manner 'in which groups of bristles are anchored orassembled at their'root portions and the arrangement of the brush in the vicinity of such root portions, regardless of the general shape or style of the brush.

In the drawings:

Fig. lis a general perspective view of one form of the brushof the present'invention;

Fig. 2 is a fragmentary perspective view illustrating, somewhat schematically, a stepin one method of producing the brush of the present invention;

Fig. 3 is a fragmentary perspective view'of a. group of bristles partly fabricated into'a brush assembly;

Fig. 4 is a fragmentary perspective view illustrating a further step in the brush forming method;

Fig. 5 is a cross-sectional view of means for effecting a further step in the method of forming the brush of Fig. 1; and

Fig. 6 is a cross-sectional view showing apparatus for finally molding the hub of the brush illustrated in Fig. 1.

Like characters of reference denote like parts throughout the several figures of the drawing. Various specific methods may be employed in assembling groups of bristles for fabrication into a complete brush. The essential characteristic of the preferred method is that alternate layers of wire bristles and gum strips are assembled in such a way that the intervening gum strips are located at points which will ultimately be the base of the bristles, and each gum strip may readily be subsequently pressed into intimate engagement with the individual bristles of the rows lying at each side of such gum strip. A gum strip is interposed between each individual layer of bristles. to form a homogeneous solid portion at the base of the bristles with each individual bristle completely surrounded by rubber, save where such bristle may lie directly against another bristle, and with substantially no voids in such base region.

By way of example, Fig. 2 illustrates a mandrel H) which is mounted for rotation about its longitudinal axis in any desired manner, a journal II for so mounting the mandrel being illustrated in Fig. 2. Mandrel IB is substantially square in cross-section and has longitudinal grooves [2 extending along the mid-portions of each of its sides.

The gum strips referred to above are, in the specific embodiment here being described, strips of unvulcanized rubber which are somewhat tacky and adhesive. In beginning to fabricate a brush or group of brush bristles, a gum strip i3 is laid along each longitudinal edge of mandrel ID as shown in Fig. 2. A continuous helical layer of wire is then wound upon the mandrel as at I 5, the mandrel being rotated in any desired manner toeffect such winding, and wire being fed thereto from any desired supply, the wire being designated l6 in Fig. 2.

Also, as shown in Fig. 2, two pairs of crimping rolls l1 and I8 are arranged to engage the wire in its passage to mandrel I0. Each pair of crimping rolls has parallel axes for intermeshing engagement and the axes of the two pairs of rolls are at right angles to each other so that the wire is given a generally helical crimp formation prior to its arrival at mandrel l9. While crimped bristles are generally desirable in the case of metallic bristles, it is to be understood that crimping is not necessary in the case of certain bristle materials and in the case of brushes having other special qualities and specifications.

After a complete layer of bristles hasbeen wound, as at [5, four more gum strips are applied along the edges of mandrel in as at 20, the strips 20 overlying the layer of bristles I5. Following this, asecond layer of bristles is wound helically upon mandrel ID as at 2i in like manner and in each case the tension of wire l6 as it is being wound upon mandrel l may be maintained at such degree that the individual windings of wire upon the mandrel will embed themselves into the underlying gum strips at the corners of the mandrel to a sufiicient degree. The

number of successive layers of wire as at l and 4 2| will vary according to the size and general design of the brush to be fabricated.

When the desired number of layers of wire bristles and intervening gum strips have been wound, a parting tool is passed through each of the grooves l2 to separate the wound assembly into four groups of assembly bristles, each of which generally resembles the preliminary assembly illustrated in perspective in Fig; 3. This parting tool may be in the form of a grinding wheel having a relatively narrow or acute-angled peripheral edge, known as an abrasive cut-ofi' wheel, or any other mechanical shearing device may be employed as may be found suitable and expedient. The adhesion between the bristles and the gum strips as effected in the winding operation is 'sufficient to render each individual subassembly, as illustrated in Fig. 3 and designated 24, self-sustaining for further fabricating.

A further description of the method of fabricating one form of the brush of the present invention contemplates the formation of a brush having radial bristles. Fig. 4 indicates schematically an arbor or mandrel 25 for assembling the group of bristles designated 24 with one or more binding wires, one of which is illustrated in Fig. 4 at 26, and for winding the assembled bristles and binding wires into annular form with the bristles extending generally radially outwardly. The angle which the bristles make in Fig. 4 is fairly acute. However, the nature of the bristle material may be such that, when they are cut from the mandrel, they spread and form a more obtuse angle. In such instances, it will be desirable to make the bristle angle more acute before proceeding to wind the bristle assembly into circular form. This may be done by further bending the bristle assembly in an ordinary bending brake such as is well-known in the sheet metal art. One end of binding wire 26 may be bent laterally and inserted radially into a slot 21 in arbor 25 as at 28 and the bristle assembly 24 placed beneath the binding wire 26 so that, when. both are subsequently wound upon arbor 25 by rotating the latter, binding wire 26 will be placed firmly into the apex of the angle formed by the bristle assembly 24. It is to be understood that only a part of the length of bristle assembly 24 is illustrated in Fig. 4.

The length of the bristle assembly 24 is such that one complete rotation of arbor 25 will wind the bristle assembly 24 into circular form and result in its ends substantially meeting at slot 21 with one circular turn of binding wire binding the circular bristle assembly about arbor 25. The rotation of arbor 25 may then be continued to lay or wind additional continuous turns of the binding wire 26 which will vary in number according to the design of the brush. In the specific form illustrated in Figs. 5 and 6 four continuous turns of the binding wire 26 are illustrated. It may, in certain instances, be desirable toplace an additional gum strip in the apex of the angle of assembly 24 prior to laying the binding wire 26 therein.

After the desired number of turns .of binding wire are wound on mandrel 25 the trailing end of the binding wire is severed and the end 28of the binding wire is swung out of slot 21. The two ends of the binding wire are then twisted about each other and the thus twisted ends are bent downwardly into the apex of the bristle assembly to lie along the circularly extending turns of binding wire. If sufiicient turns of binding wire are present, the ends need not be twisted together beanie! orotherwise 'clireetly' -seeured. The friction of -adjacentbunched turns will be sufiicient topre- -ventany tendency of the binding wires to unwind by intersliding of adjacent turns of wire in is further intimately pressed about the individual bristles of the assembly. In actual practicethis may be accomplished without removing the .bristle and binding wire assembly from arbor '25, and in Fig.5 the arbor 25 is shown as comprising the central guiding spindle of this pressing apparatus.

fihe arbor 25 is 's'hown generally horizontal in Fig.4 and vertical inFig. 5, but the apparatus may be arranged in either way without affecting the principles of thepresent invention. Arbor ZS-may have a fixed end or bottom plate 30, and a movable pressing plate 3| is slidably disposed upon arbor 25. As illustrated in Fig. 5, pressing movement of plate 3! toward plate 30 by hy- "draulic pressure, mechanical pressure, or in any desired manner, produces the required compacting of the gum at the base of the bristles and causes the individual bristles to extend radially outwardly in compact form.

The nature ofthe cut-off. operation which separates the assembled bristles from mandrel In is :suchthat subsequenttrimming of the outerends of the bristles is desirable. This may be accomplished after the plates 30-and 3l have pressed and compacted the bristles and the rubber at their roots and with the brush still held firmly between the plates. As shown in Fig. 5 the plates 30 and 3| are just slightly smaller than .thede- 'siredgfinished outside diameter of the "brush so that an abrasive cut-01f wheel can be located just outside of plates 30 and 3!, the latter beingro- 'tatedto present'the excess bristles shown in Fig.

5 to the wheel for trimming the periphery of the brush to size. Referring to Fig. 5, the cut-off wheel would be located with its horizontal center line coincident with the central horizontal plane of the brush.

After the bristles and binding wires are thus brought substantially to the final relative positions they assume in the finished brush, the entire assembly is placed in a mold element 35 and a complementary mold element 35 is placed thereover. Additional unvulcanized rubber is introduced to form a complete hub 31 of the ultimate brush. This additional rubber may be introduced in various ways. In one practical embodiment, a relatively flat rubber annulus is first laid in the annular cavity 38 of mold 34. The binding wire and bristle assembly is then placed upon this rubber annulus and a second smaller rubber annulus is placed concentrically within the bristle assembly. A third rubber annulus hire the first one is then placed concentrically upon the bristle and binding wire assembly, the several rubber annuluses being subsequently pressed, together with the rubber already in association with the root portions of the bristles, into the desired form as defined by the annular cavity 39 of upper mold element 35 and the cavity 38 of mold 34 by bringing the two mold elements forcibly together. The complete assembly may then be vulcanized to form a unitary brush with the hublcomprising a hollow: resilient annulus in in timate contact with all of the turns of the binding" wire and with the individual bristles from their baseat the binding wire to ya point radially outwardly, which is approximately equivalent to the outer diameter ofthe flanges-of hub 31. This vulcanization maybe effected either in the-mold 34, 35 or inany other desired manner.

It :may be desired to use :a different rubber batch- ,ccmposition for. the smaller of the three rubber annulusesthan .for the two which form the flan'gesof the hub so that a harder rubber inner hub portion is provided, the flanges being relatively more. resilient and flexible.

Numerous variations in the mode of winding the bristle wires or vstrandscmay be employed without departingffrom the principles of the present invention. For instance, while a single :wire it is shownin Fig.2,several wires or strands may bewound or laid-simultaneously, either side by side through the same xcrimpingrolls or indesuccessive layers and additional gum strips need be applied along the edges of mandrel ID only when such oozing hasreachedits limit. This will vary :depending on the diameter of the bristle wire, the degree of tension withwhich it is wound,

the character andathicknessaof thegumstrips,

and other factors.

After the initial .gum strips l3 are applied to mandrel l0, additional latex or unvulcanized rubber maybe applied to the surfaces of the wires at theedges 0f. mandrel loin liquid or semiliquid form as by brushing, instead of usingadditional gum strips. Brushing means may be so located as to be automatically engaged by. the wires at the edges of mandrel II] as the latter rotates in winding the bristles.

It will be observed that the ultimate brush of the present invention is characterized by the fact that the bristle density is absolutely uniform throughout with each individual bristle extending in a true radial direction. In brushes of the prior art the bristles are generally arranged in a series of tufts or bunches so that the bristles of one tuft or bunch must extend over or meet with the bristles of the next tuft or bunch. As a result, the bristle density is generally lower, or at least different, midway between individual tufts or bunches than at the center of individual tufts or bunches. Also, it is generally necessary for certain of the bristles to depart from true radial or perpendicular extent in order to secure some semblance of uniform bristle distribution at the extremities of the bristles. No such deviation or compromise from the ideal theoretical arrangement is required in the brush of the present invention.

While reference is had herein specifically to the use of rubber as a component of the brush and in pursuance of the method of the present invention, it is to be understood that the spirit of the invention embraces any substitute or equivalent materials, either natural or synthet c terial that may be cured or'advanc'ed by heat,

may be employed.

What is claimed is:

l. The method of making a brush element which comprises disposing a strip of settable adhesive material along the surface of a holder, winding a. continuous, helical bristle-forming strand about said holder substantially at right angles to said strip of material whereby the several turns of said strand become embedded locally in said strip, severing the wound strands parallel to the line of extent of said strip to provide multiple bristle portions extending perpendicularly from said strip, and flattening the assembly thus produced in return bent form to cause bristle portions extending from the opposite sides of said strip to lie in juxtaposition and provide a uniform and unitary bristle assembly.

2. The method of making a brush element which comprises disposing a strip of settable adhesive material along the surface of a holder, winding 3. continuous, helical bristle-forming strand about said holder substantially at right angles to said strip of material whereby the several turns of said strand become embedded locally in said strip, winding additional layers of strand over the strand thus wound and intermittently applying any necessity additional adhesive material between the layers of strands to insure complete embedding of all turns of strand along the area defined by said adhesive strip, severing the Wound strands parallel to the line of extent of said strip to provide multiple bristle portions extending perpendicularly from said strip, and flattening the assembly thus produced to cause bristles extending from the opposite sides of said strip to lie in juxtaposition to form a uniform and unitary bristle assembly.

3. The method of making brush elements which comprises disposing strips of settable adhesive material along parallel lines equally spaced about the surface of a holder, winding a continuous, helical bristle-forming strand about said holder substantially at right angles to said strips of material whereby the several turns of said strand become embedded locally in said strips, severing the wound strands along lines parallel to the line of extent of said strips and midway between each pair of strips to provide a number of brush elements equal to the number of strips initially provided about the holder, each brush element comprising multiple bristle portions extending perpendicularly from its associated strip, and flattening the assemblies thus produced in return bent form to cause bristle portions extending from the opposite sides of said strip to lie in juxtaposition to form uniform and unitary bristle assemblies.

4. The method of making a brush element which comprises disposing a strip of settable adhesive material along the surface of a holder, winding 3, continuous, helical bristle-forming strand about said holder substantially at right angles to said strip of material whereby the several turns of said strand become embedded in said strip, severing the wound strands parallel to the line of extent of said strip to provide multiple bristle portions extending perpendicularly from said strip in angularly disposed rows, placing binding wire means in the apex of such angle, flattening the assembly thus produced in return bent form to securely press adhesive material into contact with said binding wire means and to cause bristles extending from the opposite sides of said strip to lie in juxtaposition to form a uniform and unitary bristle assembly.

HOWARD W. BIBLE, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 376,800 Frisbie Jan. 24, 1888 1,259,571 Wiens Mar. 19, 1918 2,288,337 Whittle June 30, 1942 2,294,480 Rohweder Sept. 1, 1942 2,296,949 Roberts Sept. 29, 1942 2,303,386 Peterson Dec. 1, 1942 

